netfilter: ipset: fix a missing check of nla_parse

When nla_parse fails, we should not use the results (the first
argument). The fix checks if it fails, and if so, returns its error code
upstream.
Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>

net/netfilter/ipset/ip_set_core.c

@@ -1544,10 +1544,14 @@ call_ad(struct sock *ctnl, struct sk_buff *skb, struct ip_set *set,
 		memcpy(&errmsg->msg, nlh, nlh->nlmsg_len);
 		cmdattr = (void *)&errmsg->msg + min_len;
 
-		nla_parse_deprecated(cda, IPSET_ATTR_CMD_MAX, cmdattr,
-				     nlh->nlmsg_len - min_len,
-				     ip_set_adt_policy, NULL);
+		ret = nla_parse_deprecated(cda, IPSET_ATTR_CMD_MAX, cmdattr,
+					   nlh->nlmsg_len - min_len,
+					   ip_set_adt_policy, NULL);
 
+		if (ret) {
+			nlmsg_free(skb2);
+			return ret;
+		}
 		errline = nla_data(cda[IPSET_ATTR_LINENO]);
 
 		*errline = lineno;